Understanding Positive Displacement Screw Pumps: A Complete Guide

1
Understanding Positive Displacement Screw Pumps
A Complete Guide

• When it comes to fluid transfer and handling, the
  right pump can make all the difference in
  ensuring efficiency, accuracy, and durability.
  Among the various pump types, positive
  displacement screw pumps stand out as a highly
  effective solution for moving a wide range of
  liquids, from thick and viscous fluids to thin
  liquids. Lets dive into the specifics of
  positive displacement screw pumps to understand
  how they work, their applications, and why they
  are preferred in many industries.
• What Are Positive Displacement Screw Pumps?
• A positive displacement screw pump is a type of
  pump that uses a rotating screw mechanism to move
  fluid through a chamber. Unlike centrifugal
  pumps, which rely on the speed and energy of the
  liquid, positive displacement pumps operate by
  trapping a fixed volume of fluid and moving it
  through the system. This "positive displacement"
  ensures that the same amount of liquid is moved
  with each revolution, regardless of changes in
  pressure or flow resistance.
• In a screw pump, a screw shaft (or screws)
  rotates inside a housing, creating pockets that
  trap and transport the fluid. These screws can
  either be single screw or twin screw (with two
  screws rotating in a synchronized manner). The
  design allows for precise, controlled fluid
  movement, making it suitable for various
  industrial applications.
• How Do Positive Displacement Screw Pumps Work?
• The operation of a positive displacement screw
  pump can be broken down into the following steps
• Fluid Intake Fluid enters the pump through an
  inlet port. As the screw or screws rotate, they
  create pockets that gradually expand, drawing in
  the liquid.
• Fluid Transport As the screw continues to turn,
  the trapped volume of fluid is transported along
  the length of the screw. The rotation moves the
  fluid through the housing in a continuous,
  predictable manner.
• Fluid Discharge The liquid is eventually
  expelled from the pump through the outlet port.
  The fluid is discharged at a consistent rate, and
  the flow remains steady even if the pressure
  changes in the system.
• Key Features and Benefits of Positive
  Displacement Screw Pumps
• Precise Flow Control Since each revolution moves
  a fixed volume of fluid, screw pumps offer
  precise flow control, making them ideal for
  applications that require accurate metering of
  liquids.

2

• Self-Priming These pumps can handle air or gas
  that may enter the system without causing
  operational disruptions, making them self-priming
  in many cases.
• Durability and Reliability Positive displacement
  screw pumps are built to last, with durable
  materials and robust construction that can handle
  high pressures and temperatures, offering
  reliable service over time.
• Applications of Positive Displacement Screw Pumps
• Positive displacement screw pumps are highly
  versatile and can be used in various industries,
  including
• Oil and Gas These pumps are widely used in the
  oil and gas sector for transferring crude oil,
  petroleum products, and other viscous fluids.
  Their ability to handle high- viscosity liquids
  without compromising performance is essential in
  this industry.
• Food and Beverage In food processing, positive
  displacement screw pumps are used to transfer
  products such as oils, syrups, sauces, and even
  doughs. Their precise flow and ability to handle
  delicate products without damaging them make them
  popular in the food industry.
• Pharmaceuticals Accurate dosing and
  contamination-free transfer are critical in the
  pharmaceutical industry, where screw pumps excel
  due to their ability to handle viscous liquids
  and maintain hygiene standards.
• Chemical Industry These pumps are used to handle
  aggressive chemicals, such as acids, bases, and
  solvents, where precise flow control and
  resistance to corrosion are required.
• Water Treatment Screw pumps can also be found in
  water treatment facilities, where they are used
  for transporting slurries, sludge, or other
  wastewater materials
• that may have high viscosity or contain solid
  particles.
• Marine and Automotive Positive displacement
  screw pumps are used in marine and automotive
  industries for applications like fuel transfer,
  lubrication, and cooling systems.
• Types of Positive Displacement Screw Pumps
• Single Screw Pumps These pumps use one large
  screw that rotates within a cylindrical casing.
  They are ideal for handling viscous liquids and
  offer a smooth, continuous flow.
• Twin Screw Pumps These pumps use two screws that
  rotate in opposite directions inside a casing.
  They are highly efficient and typically used for
  pumping low to medium viscosity fluids.
  Twin-screw pumps also tend to operate with
  minimal

3
right one for your specific needs, ensuring
optimal performance and longevity in your
operations. With their ability to handle
challenging fluids, maintain steady flow, and
offer durability, positive displacement screw
pumps continue to be a popular choice for a wide
range of applications, making them an invaluable
tool in the world of fluid handling.